Using high frame rate CMOS sensors for three-dimensional eye tracking

A novel three-dimensional eye tracker is described and its performance evaluated. In contrast to previous devices based on conventional video standards, the present eye tracker is based on programmable CMOS image sensors, interfaced directly to digital processing circuitry to permit real-time image acquisition and processing. This architecture provides a number of important advantages, including image sampling rates of up to 400/sec measurement, direct pixel addressing for preprocessing and acquisition, and hard-disk storage of relevant image data. The reconfigurable digital processing circuitry also facilitatesin-line optimization of the front-end, time-critical processes. The primary acquisition algorithm for tracking the pupil and other eye features is designed around the generalized Hough transform. The tracker permits comprehensive measurement of eye movement (three degrees of freedom) and head movement (six degrees of freedom), and thus provides the basis for many types of vestibulo-oculomotor and visual research. The device has been qualified by the German Space Agency (DLR) and NASA for deployment on the International Space Station. It is foreseen that the device will be used together with appropriate stimulus generators as a general purpose facility for visual and vestibular experiments. Initial verification studies with an artificial eye demonstrate a measurement resolution of better than 0.1° in all three components (i.e., system noise for each of the components measured as 0.006° H, 0.005° V, and 0.016° T. Over a range of ±20° eye rotation, linearity was found to be <0.5% (H), <0.5% (V), and <2.0% (T). A comparison with the scierai search coil technique yieldednear equivalent values for the systemnoise and the thickness of Listing’s plane.     

Bogus Mystery about Linguistic Competence

The paper considers a version of the problem of linguistic creativity obtained by interpreting attributions of ordinary semantic knowledge as attributions of practical competencies with expressions. The paper explains how to cope with this version of the problem without invoking either compositional theories of meaning or the notion of `tacit knowledge' (of such theories) that has led to unnecessary puzzlement. The central idea is to show that the core assumption used to raise the problem is false. To render precise argument possible, the paper first identifies and removes some relevant semantic indeterminacy in philosophical talk of `semantic knowledge' and `information'. This yields rules for attributing the two to human speakers and information-processors, respectively. The paper then shows, first, that ordinary speakers qualify as possessing all along an other than finite and definite stock of semantic knowledge and, second, that a very simple information-processor running a procedural semantics qualifies as possessing an analogous stock of semantic information. The second result is used to bring out that the first is neither unduly impressive nor particularly puzzling.     

Program Context,Sensation Seeking,and Attention to Televised Anti-Drug Public Service Announcements

This study examined effects of message and program sensation value, sensation seeking, and drug use on visual attention to televised anti-drug public service announcements (PSAs) among 318 18–22-year-olds, who were placed individually in a simulated home environment with the opportunity to read from print media selections and/or watch a half-hour TV program including two presentations of the test PSA. The TV program was high or low in sensation value. High sensation seekers paid greater attention to high sensation value programming and to PSA embedded in such programming, whereas low sensation seekers paid greater attention to PSA embedded in low sensation value programs. Ongoing attention to a program may help to sustain attention to a subsequent PSA. The findings relate to an activation model of information exposure and indicate that program sensation value and sensation seeking are important factors to be considered in the placement oftelevised drug abuse prevention messages.     

Terrorism as Collective Communication: The Collective Communication Model of Terrorism (CCMT)

This paper proposes that the psychological and behavioral effects of terrorist threat can be understood as a collective communication process that occurs between terrorists and their potential victims. Based on classic communication theory, terrorists are regarded as the senders of a specific collective message (such as ‘stop oppressing our culture’); a terrorist incident as the collective message itself (through its performance, modality and targets); and the potential victims as its collective receivers (who interpret the intention of the attack as a function of their pre-existing attributes, such as traits or salient social identities). The perception of terrorism as a dynamic and interactive process between collective senders, messages and receivers opens new theoretical perspectives regarding whether (a) terrorism can be successful in reaching its collective aim; (b) if it is interpreted as rational or irrational; and (c) how to counteract the vicious, cyclical relationship between terrorism and counter-terrorism. Previous findings on the psychology of terrorism can be organized within this theoretical framework, and the psychological impact of varying attributes of the perpetrators (senders), incident (message), and the reactions of the potential victims (receivers) systematically investigated. A series of self-conducted studies are also reviewed and found to provide direct support for the collective communication model of terrorism.